1. Field of the Invention
The present invention relates to a virtual transmission system enabling changing the use of an application software, such as for personal computer transmission, personal fax transmission, and other types of transmission, in a user mode, without actually changing the application software itself. The user mode is a non-exclusive mode wherein access to system data and interfaces that can be used are limited.
2. Description of the Related Art
Recently, a variety of different types of application software are available for enabling personal computers to transmit data to and receive data from peripheral or remote devices. For example, application software is available for enabling personal computers to perform data transmission and reception with a peripheral printer over a cable or with a remote facsimile machine over a telephone line. Transmission application software is generally configured to perform reception and transmission of data over a serial port connected to a modem.
There is a demand to change the use of transmission application software. For example, it would be desirable if transmission application software for performing transmission and reception of data through a serial port could be used to perform transmission and reception of data through a parallel port, instead of a serial port. Also, it would be desirable if transmission application software could be used to check, using the personal computer, transmitted and received data.
However, in order to fill change use of the transmission application software, the transmission application software itself must be rewritten or the kernel mode program must be greatly changed. It is difficult to rewrite transmission application software. Further, the kernel mode program is an exclusive processor mode, which is capable of accessing the system data and hardware, and so is also very difficult to rewrite.